<%@ page contentType="image/jpeg"
	import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"%>
<%@ page import="java.io.OutputStream"%>

<%

	//try{
	
	boolean ifSkip = false;
	String token = request.getParameter("token");
	if (null != token && "true".equals(token)) {
		ifSkip = true;
	}

	//设置页面不缓存
	response.setHeader("Pragma", "No-cache");
	response.setHeader("Cache-Control", "no-cache");
	response.setDateHeader("Expires", 0);

	// 在内存中创建图象
	int width = 80, height =20;
	BufferedImage image = new BufferedImage(width, height,
			BufferedImage.TYPE_INT_RGB);

	// 获取图形上下文
	Graphics g = image.getGraphics();

	//生成随机类
	//Random random = new Random();

	// 设定背景色
	g.setColor(new Color(255, 255, 255));
	g.fillRect(0, 0, width, height);

	//设定字体
	g.setFont(new Font("sansserif", Font.BOLD, 20));

	//画边框
	//g.setColor(new Color());
	//g.drawRect(0,0,width-1,height-1);

	// 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
	/*
	g.setColor(new Color(240,240,240));
	for (int i=0;i<155;i++)
	{
	 int x = random.nextInt(width);
	 int y = random.nextInt(height);
	        int xl = random.nextInt(12);
	        int yl = random.nextInt(12);
	 g.drawLine(x,y,x+xl,y+yl);
	}
	 */

	// 取随机产生的认证码(4位数字)
	/*String sRand="";
	for (int i=0;i<4;i++){
	    String rand=String.valueOf(random.nextInt(10));
	    sRand+=rand;
	    // 将认证码显示到图象中
	    g.setColor(new Color(0,0,0)); //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
	    g.drawString(rand,13*i+6,16);
	}
	 */
	/*String strRegNo =(String)session.getAttribute("checkNum");
	if (strRegNo==null||strRegNo.equals(""))
	{*/
	Random random = new Random();
	// 取随机产生的认证码(4位数字)
	String strRegNo = "";
	for (int i = 0; i < 4; i++) {
		String rand = String.valueOf(random.nextInt(10));
		strRegNo += rand;
	}

	//skip if has token
	if (ifSkip) {
		strRegNo = "1111";
	}
	// 将认证码存入SESSION
	session.setAttribute("rand", strRegNo);
	//}
	g.setColor(new Color(0, 0, 0)); //调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
	g.drawString(strRegNo, 6, 16);

	// 将认证码存入SESSION
	//session.setAttribute("rand",sRand);

	// 图象生效
	g.dispose();

	OutputStream os = response.getOutputStream();

	// 输出图象到页面
	ImageIO.write(image, "JPEG", os);

	os.flush();
	os.close();
	os = null;

	//测试代码
	//throw new Exception();
	//释放资源
	response.flushBuffer();
	out.clear();
	out = pageContext.pushBody();
	//System.gc();
	/*}
	 catch(Exception e)
	 {
	 e.printStackTrace();
	 }
	 finally
	 {	
	
	 }*/
%>